Recent years have seen a rising trend in the earth’s temperature due to global warming. This rising temperature coupled with extreme weather events has the ability to significantly affect the health of people around the world. According to this National Geographic article, dangerous heatwaves are far more common than anyone realised, killing people in more than 60 different parts of the world every year.
People who dwell in the wet tropics are most in danger since even little changes in average temperature or humidity can cause fatalities. However, if heat and extremely high humidity are present, even at moderate temperatures of less than 30 degrees Celsius, heat can be fatal.
Climate change can have an impact on human health by altering the intensity, length, or frequency of health issues, as well as by posing new, unexpected health problems or health threats in places or populations where they have not previously occurred. Despite the fact that everyone is at risk for health problems connected to the environment, not everyone is harmed in the same ways.
GlobalChange.gov's Climate and Health Assessment on Temperature-Related Death and Illness has four major findings:
Future Increases in Temperature-Related Deaths
Even Small Differences from Seasonal Average Temperatures Result in Illness and Death
Changing Tolerance to Extreme Heat
Some Populations at Greater Risk
Does Climate Change affect Heat-Related Illness?
Heat stress and heat exhaustion cases have seen an unprecedented rise with the rising temperature, especially for people who live in the tropical region, the elderly, outdoor workers, and people with obesity, heart diseases and diabetes. While heat exhaustion is a mildly serious condition that has to be treated right away. Heat stroke is a life-threatening medical emergency. Additionally, heat has been found to impair thinking and reduce productivity.
A heat wave, a period of prolonged abnormally high surface temperatures relative to those normally expected, may span several days to several weeks. For a variety of causes, heat waves can be lethal. All three organs—hearts, brains, and lungs—are vulnerable to heat stress, and when they get overheated, they fail. The failure of these organs has been primarily blamed for higher fatality rates during heat waves.
2022 heatwaves around the globe have seen a very high mortality rate, along with disruptions in water, energy, and agricultural systems. 2022 heatwaves broke records for temperature highs in Pakistan and India resulting in the loss of more than 90 lives. Several factors determine an individual's ability to dissipate heat. Age seems to be a major factor, with pre-pubescent children and older individuals having significantly lower heat-expulsion capacities than adults.
Persistent heat waves from June to August 2022 caused evacuations and heat-related fatalities in certain regions of Europe. The highest temperature recorded was 47.0 °C (116.6 °F) in Pinhão, Portugal, on 14 July. As a result of the heatwaves, widespread droughts have occurred across the continent.
Heat waves can impact economies as well as people and wildlife by causing massive wildfires. The image below shows the Fire Danger Forecast (ECMWF/ Fire Weather Index) over Europe. For a large portion of Portugal, red fire warnings were in force due to the hot weather's increased potential for wildfires.
Climate models have been used to predict what the global average temperature will be throughout this century. The image below shows what climate models predict. The best-case scenario (RCP 2.6) keeps warming to a maximum of 1° C over the course of a century. The world heats by an average of more than 4° C under the worst-case scenario (RCP 8.5). Three degrees may not seem like much, but for a sizeable portion of the human population, it might be the difference between life and death.
Research shows that as the average temperature would go up, the frequency and intensity of heatwaves will grow dramatically as well as the extent of lethal heatwaves would increase if the earth follows the RCP 8.5 scenario affecting three-quarters of the human population by 2100.
Does climate change exacerbate infections?
Warming combined with changes in the water cycle has raised concern about how climate change may influence the spread of vector-borne diseases. As cold-blooded species known as "ectotherms," insects, for example, must seek out warmer or cooler settings in order to maintain a consistent body temperature. Climate change's amplification of the water cycle is especially important for mosquito reproduction since it takes place in water. Temperature sensitivity also applies to the viruses and parasites transmitted by insect vectors.
Temperature and rainfall also favour water-borne disease outbreaks causing cholera and other diseases, algal booms etc. Warmer temperatures promote the growth of pathogens as well.
All in all, the body's ability to regulate its internal temperature is jeopardised by extreme temperatures, which directly affect health. A lack of internal temperature control can lead to a number of illnesses, including hyperthermia, heat exhaustion, heat cramps, heat stroke in the presence of severe heat, and hypothermia and frostbite in the presence of extreme cold. Temperature extremes have the potential to exacerbate chronic conditions such as diabetes, and lung, brain, and heart conditions.
Where to go from here?
The Health Effects Of Global Warming: Developing Countries Are The Most Vulnerable
The Impact of Climate Change on Our Health and Health Systems. Source: Commonwealth Fund
The Global South is the climate movement’s unsung leader. Source: Nature Climate Change
Here’s how heat waves can impact economies, as well as people and wildlife
Swarnalee, this is a very nice summary you put together. This is a huge topic and there are so many angles that you can take from here. A regional perspective would be nice to have as we start experiencing higher levels of climate change anomalies.